Dental chair

ABSTRACT

The patient-supporting structure of the chair is carried on a vertically adjustable platform which rides up and down on a laterally displaced post; the platform is kept level by vertically spaced opposed rollers riding on vertical tracks formed on the post, there being two sets of rollers acting in planes at right angles to each other so that lateral displacement and angular movement are prevented. The platform may move down practically to floor level. An instrument console is mounted for horizontal pivoting and vertical sliding on an offset shaft and has a lost motion connection to the platform so that it follows it only in the upper part of its adjustment range.

[111 3,826,531 [451 July 30, 1974 1 DENTAL CHAIR [76] Inventor: Richard W. Page, PO. Box 258B,

Chatham, Mass. 02633 [22] Filed: May 15, 1972 [21] Appl. No.: 253,395

[52] U.S. Cl. 297/188, 312/209 [51] Int. Cl A47c 7/62, A6lc 19/00 [58] Field of Search 297/188, 170, 284, 345, 297/348, 330; 108/138; 32/22; 312/209 [56] References Cited UNlTED STATES PATENTS 1,952,744 3/1934 Chapman 297/345 X 2,187,283 l/.l940 Schcvtz.. 297/348 X 2,608,239 8/1952 Gorden.. 297/348 2,679,283 5/1954 Mahone 297/348 2,859,063 11/1958 Underland 297/348 3,089,741 5/1963 Burton 297/345 X 3,194,187 7/1965 Linder et a1. 297/345 X 3,304,609 2/1967 Horowitz et a1. 108/138 Hunter et a1 108/138 X Primary ExaminerJames T. McCall Attorney, Agent, or Firm-W. R. Hulbert [5 7] ABSTRACT The patient-supporting structure of the chair is carried on a vertically adjustable platform which rides up and down on a laterally displaced post; the platform is kept level by vertically spaced opposed rollers riding on vertical tracks formed on the post, there being two sets of rollers acting in planes at right angles to each other so that lateral displacement and angular movement are prevented. The platform may move down practically to floor level. An instrument console is mounted for horizontal pivoting and vertical sliding on an offset shaft and has a lost motion connection to the platform so that it follows it only in the upper part of its adjustment range.

8 Claims, 4 Drawing Figures Condon 297/188 PATENTED Jill-3 0 SHEET 1 [IF 4 PATENTEU SHEU 2 0F 4 Pmmgu JULSOISN sumanra' snieiunra 1: III I I lllllil v I 1 DENTAL CHAIR CROSS-REFERENCE TO RELATED APPLICATION The present application is directed to an improvement on the dental chair disclosed in prior application of Richard W. Page, Ser. No. 135,634, filed Apr. 20, I971, now U.S. Pat. No. 3,724,894, for Dental Operating Chair.

FIELD OF THE INVENTION eliminates the obstructions under the chair, but is subject to heavy tilting forces, requires considerable headroom and tends to expose lubricated surfaces which require somewhat awkward cover arrangements. Jointed arrangements of various kinds have been proposed, but involve excessive stresses at certain points, present dead-center problems in some positions and are comparatively complicated, particularly when it is desired to have the height adjustment independent of the position of the patient.

SUMMARY OF THE INVENTION The vertically adjustable platform takes the form of a bracket which slides up and down a post to one side of the chair, the bracket being positioned horizontally by means of rollers riding on tracks forming part of the post and being moved up and down by means of a vertical screw. The base which supports the post comprises horizontal elements extending from the post to a line well beyond the center of gravity of the supported chair elements and patient and to points well spaced from the center of gravity along the chair center line, insuring the stability of the entire structure. At the same time, the entire space under the chair is substantially free of obstruction by the base elements, along one side of the chair, while the space along the other side accommodates only a base element which may be two or three inches high, leaving ample space for the feet and legs of the dentist and assistant. The platform may be brought as close to floor level as required and may itself be comparatively thin, so that positioning of the patient in preferred operating positions is facilitated. The rollers which guide the bracket are arranged in vertically and horizontally displaced opposed sets in two perpendicular planes, so as to eliminate axial thrusts on the rollers and permit operation without lubrication of the roller tracks.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 is a somewhat schematic plan view of a dental operating chair embodying the invention in a preferred FIG. 3 is a horizontal section on a larger scale;

FIG. 4 is a side elevation, to an intermediate scale.

In the drawing, there is indicated in dot-dash outline a chair superstructure A, which is carried by a platform or bracket structure B composed of two arms secured to a vertically moveable carriage C, which is adjusted to, and held at, any desired height on post D by motordriven screw E. The post is mounted on an L-shap'ed pedestal base which extends beyond the center line of superstructure A and its center of gravity, including the the patient, as well as the center of gravity of the parts supported by the carriage C.

A vertical shaft F, offset from carriage C and post D, supports a dental instrument console indicated schematically at G, the console being pivotal horizontally about post D and vertically slidable thereon. The console is coupled to carriage C, as described below, for positioning it properly in relation to the chair superstructure A.

Post D may be, as shown, of uniform cross-sectional form, adapted to manufacture as an extruded unitary element, or it may be a composite structure of any of a variety of types, where preferred. It has a hollow gen erally rectangular form, a shape having high moment of inertia, with principal axes directed along the legs of the L-shaped pedestal.

The post body 10 has eight undercut grooves 11, two to each face of the rectangle, forming two pairs of opposed symmetrical sets in two pairs of spaced parallel planes, arranged at right angles to each other. Each groove holds a piece of rectangular bar stock 12, which is preferably of hardened steel and serves as a track for the rollers of carriage C. One wide face of the post has an additional pair of grooves 13 in which two walls 14, forming part of a housing for screw E, fit and are fastened in place, as by screws 15. Walls 14 are formed with slots 16, in which plates 17 are slidably mounted so as to close off the space accomodating screw E, above and below the carriage C.

Post body 10 is secured to the pedestal base by four screws 18, adjacent its four corners. The top of the post is covered by a cap member 19, secured to the post body by screws 20, and having a socket 21 supporting anti-friction thrust bearing 22 for screw E, and a bore 23 containing a nylon bushing slidably receiving the shaft F, on which the console G is carried.

Pedestal part 25 has a table 26 to which the post is secured by screws 18, and a side wall 27 to which the other pedestal part 28 is bolted or welded. The part 25,

. below table 26, forms a housing for motor M and worm wheel assembly W which rotates screw E. The reduced upper end of screw E passes through thrust bearing 22 in socket 21 and is supported by nut and lock nut 30,31 so that the screw E is hung from the top of the post and carries the weight of the carriage C and associated parts in tension.

Carriage C comprises right and left members 32,33 secured together by a front cover plate 34 and back cover 35, the cover elements being secured to members 32,33 by screws 36,37. Members 32,33 have inner vertical walls or ribs 38 forming eight pairs of walls positioned respectively opposite the post rail grooves 11. The walls 38 are bored to take shafts 39 and 40 upon which the wheels or rollers 41 are carried in position to ride on the rails 12. Rollers 41 have clearance from the overhanging edges 11' of the rail grooves 11 and from the walls 38, so as not to transmit any forces axially of shafts 39 and 40 upon which the rollers are carried. In consequence the surface of post D requires no lubrication. Rollers 41 are of the type commonly used as cam rollers and incorporating anti-friction bearings between hub and rim.

The carriage is equipped with two lower pairs of rollers, riding, respectively on'the rails 12 in the front and right walls of the post body 10, and two upper pairs riding on the rails,l2 of the rear and left walls of the post body 10, the upper rollers being about ten inches higher than the lower rollers. With these dimensions, the moment arm of the couple exerted by the rollers is sufficient to keep the loading of the rollers within comfortable design limits.

The carriage back cover 35 is bulged outwardly (rearwardly) to accommodate the screw housing walls 14 and carries a nut-block bracket 42, secured to member 35 by screws 43 and having a thrust projection 44 with an opening 45 which accommodates the screw E with clearance. Ball nut 46 abuts against the underside of projection 44 and is secured thereto against rotation by screw 47. As screw E turns innut 46, it accordingly raises or'lowers nut 46, thus moving the carriage C up or down. When motor M is deenergized, its drive shaft is braked, thus preventing screw E from turning and holding the Carriage C at the height to which it has been moved.

Neglecting friction, it will be apparent that'the weight of the carriage and attachedload (bracket, chair superstructure, patient, console) isbalanced by a vertical tension in screw E, which has zero moment arm about the post section short (front'to back) central axis, and a moment arm about the post section long (right to left) central axis, which is comparatively short (about one fourth that of the superstructure center of gravity).

The moment of the tension in screw E, when the carriage is at rest, adds to the pressure of rollers 41 on rails 12, and the increasing or elimination of this tension while the carriage height is being adjusted causes no reversal of over-all moments, and produces no irregularity in the movement. There is no perceptible play or looseness in the mounting of superstructure A about any horizontal or vertical axis, so that the action is smooth and rigid under all working conditions.

The console mounting shaft F comprises a lower section 50 and slightly smaller upper section51,and its vertical axis maintained in position by upper nylon bushing 24, in which the upper section 51 is slidably and rotatively received, and by bushing 52 in the offset lower end of bracket member 53, secured to carriage C by screws 54. Shaft section 50 is slidable in bushing 52, so that the movement of parts described below is obtained. e

The console G is rotatively and slidably carried on shaft F by upper and lower bearing rings 55,56 secured to the console cabinet body and fitting slidably and rotatably on the shaft section 50. Collar 57'is secured to shaft section 50 in position to abut bearing ring 56 and support the console from the carriage C for movement therewith; Collar 57 carries a slide block 58 which rides tion, with collar 57'spaced by a distance h from bushing 52. The distance h is determined by the setting of collar 57 and may vary to suit particular superstructures A and console geometries. In the case shown by way of illustration, the distance h is a little more than a foot.

In consequence of the lost motion between parts 57 and 52, the raising of carriage C and chair superstructure A at first leaves the console G in its lowermost position and then, after collar 57 engages bearing ring 52, the console moves up with carriage C and superstructure A, maintaining a fixed relation to the chair superstructure and patient.

The top and bottom of carriage C are closed off by covers fitting around post D, and there is no exposure of parts having relative movement such as to create danger of injury to the fingers of patient or others.

The platform or bracket B, which supports the chair superstructure, comprises bracket arms 65 and 66, which are secured to the left and right faces of carriage C, as by bolts or screws 67. These arms generally overlie the the pedestal sections 25 and 28, and their configuration may vary to suit the particular superstructure A with which they are used. As shown, the arms 65 and 66 extend beyond the center line of the superstructure A,fastening thereunder by means of bolt holes 67,68 and also at bolt holes 69,70 under the rear edge of the superstructure. 7

Console G may be of any of a variety of arrangements, one such arrangement being that of Page & Kilpatrick U.S.- Pat. No. 3,311,411 issued Mar. 28, I967. The head H of the console may have a telescoping mounting to permit extending it across the superstructure A and up to the head (right) end thereof. Alternatively, or additionally, the head H may swing up and down vertically about an axis in the cabinet of console G. In addition, the rotary adjustment about shaft F which is-possible without interference with the super structure A by the cabinet body about 22 /2 in the illustrated embodiment) gives considerable overhang of head H over the chair superstructure A, and permits eliminating telescoping adjustment, where desired. Similarly, the vertical movement of console G permits dispensing with vertical pivoting of head H on the conin vertical groove 59 running the length of back cover I sole body in some cases. Console G may also be swung away from the chair, (clockwise in FIG. 1), to practically any extent desired.

Shaft F is surmounted by a cap 71, which may be replaced by any of a variety of instrument, lighting, or other arrangements. Such arrangements will then adjust vertically, along with the console G.

As mentioned above, the chair superstructure may be of any of various types in addition to the molded one piece arrangement. In particular, a hinged back structure may be used (e.g., as in above US. Pat. No. 3,31 1,41 l) or a flexble structure (as in prior Page application Ser. No. 135,634 filed Apr. 20, l97l for Dental Operating Chair). All that is required for such adaptations is a sitable-rearrangement of the platform or bracket structure B.

While eight rollers 41, arranged as described are sufficient to'carry all normal working stresses, these active rollersmay be supplemented by additional upper or lower rollers facing the active rollers and level therewith. Such additional rollers may be called into action if a violent lifting or horizontal twisting force is exerted on the bracket B, as by impact of furniture, accidental dropping of a heavy object on one end of the upper structure A or attempts to twist the structure A for any reason.

What is claimed is:

1. A dental operating chair having a patientsupporting superstructure and height-adjusting support for said superstructure, characterized in that the support comprises a post positioned to one side of the superstructure, a carriage vertically moveable on said post and having bracket means extending under the superstructure to support the same on the carriage, and a vertical motor-driven screw drive for the carriage said post having rails in two sets of spaced parallel vertical planes, the planes of the two sets being at right angles to each other, and the carriage having upper rollers running on a plane of each set and lower rollers running on the remaining plane of each set.

2. A dental operating chair according to claim 1, in

which the said rollers running on the rails of a said set are free to move laterally along with the carriage in the plane of said set, and restrained from such lateral movement by the rollers engaging the other set of rails.

3. A dental operating chair having a patientsupporting superstructure and height-adjusting support for said superstructure, characterized in that the support comprises a post positioned to one side of the superstructure, a carriage vertically moveable on said post and having bracket means extending under the superstructure to support the same on the carriage, a vertical motor-driven screw drive for the carriage, a vertical shaft adjacent said post, a dental console mounted for sliding vertically of said shaft and means connecting said to of said carriage for moving the console vertically along with the carriage.

4. A dental operating chair according to claim 3, in which the means connecting the console to the carriage comprises a lost motion connection, whereby the console follows the carriage during its movement within an upper range of positions but remains at set level while the carriage moves in a lower range of positions.

5. A dental operating chair according to claim 4, in which the post is located toward the foot end of the superstructure and the console is supported for pivoting on an axis adjacent the post and on the far side thereof from the chair superstructure.

6. A dental operating chair according to claim 2, in which the post has a hollow rectangular cross-section and thesaid rails are in the four planar faces of the post.

7. A dental operating chair according to claim 6, in which the said post comprises an upper support for the said screw drive and spaced vertically extending walls forming an open sided housing therefore and included within the said carriage, the screw drive comprising a vertical screw suspended from said upper support, a nut on said screw and movable vertically by rotation thereof, a bracket fixed to the carriage and extending over said nut in abutting relation thereto and flexible means closing off the open side of said housing while permitting vertical movement of said last-mentioned bracket.

8. A dental operating chair according to claim 7, in which the said last-mentioned bracket comprises a narrow web section and the said flexible means comprises a pair of flexible strips substantially meeting above and below the same.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,8 ,53 Dated y 3 197 Inventor(s) Richard We Page It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

001. 3, line 47, after "axis" insert --is--;

and I Claim 3, col.) 5, line 33 giter "said first occurrence, insert console and delete "of" Signed and sealed this 26th day of November 1974 (SEAL) Attest:

McCOY M. GIBSON JR. c. MARSHALL DANN 1 Attesting Officer Commissioner of Patents USCOMM-DC 60376-P69 u.s. GOVERNMENT PRINTING OFFICE 19699-366-335 FORM PO-IOSO (10-69) 

1. A dental operating chair having a patient-supporting superstructure and height-adjusting support for said superstructure, characterized in that the support comprises a post positioned to one side of the superstructure, a carriage vertically moveable on said post and having bracket means extending under the superstructure to support the same on the carriage, and a vertical motor-driven screw drive for the carriage said post having rails in two sets of spaced parallel vertical planes, the planes of the two sets being at right angles to each other, and the carriage having upper rollers running on a plane of each set and lower rollers running on the remaining plane of each set.
 2. A dental operating chair according to claim 1, in which the said rollers running on the rails of a said set are free to move laterally along with thE carriage in the plane of said set, and restrained from such lateral movement by the rollers engaging the other set of rails.
 3. A dental operating chair having a patient-supporting superstructure and height-adjusting support for said superstructure, characterized in that the support comprises a post positioned to one side of the superstructure, a carriage vertically moveable on said post and having bracket means extending under the superstructure to support the same on the carriage, a vertical motor-driven screw drive for the carriage, a vertical shaft adjacent said post, a dental console mounted for sliding vertically of said shaft and means connecting said to of said carriage for moving the console vertically along with the carriage.
 4. A dental operating chair according to claim 3, in which the means connecting the console to the carriage comprises a lost motion connection, whereby the console follows the carriage during its movement within an upper range of positions but remains at set level while the carriage moves in a lower range of positions.
 5. A dental operating chair according to claim 4, in which the post is located toward the foot end of the superstructure and the console is supported for pivoting on an axis adjacent the post and on the far side thereof from the chair superstructure.
 6. A dental operating chair according to claim 2, in which the post has a hollow rectangular cross-section and the said rails are in the four planar faces of the post.
 7. A dental operating chair according to claim 6, in which the said post comprises an upper support for the said screw drive and spaced vertically extending walls forming an open sided housing therefore and included within the said carriage, the screw drive comprising a vertical screw suspended from said upper support, a nut on said screw and movable vertically by rotation thereof, a bracket fixed to the carriage and extending over said nut in abutting relation thereto and flexible means closing off the open side of said housing while permitting vertical movement of said last-mentioned bracket.
 8. A dental operating chair according to claim 7, in which the said last-mentioned bracket comprises a narrow web section and the said flexible means comprises a pair of flexible strips substantially meeting above and below the same. 